Function generators are used to deliver signals with different frequency, amplitude, modulation, value ranges, time characteristics and/or interruptions. In this context, a plurality of different signals is sometimes generated by different signal units of a function generator, wherein a plurality of signals can be delivered at different outputs of a function generator.
A test appliance which provides a function generator with different signal units for testing a device under test is known from U.S. Pat. No. 7,237,167 B2. This test appliance comprises both analog modules for the generation of analog test signals and also digital modules for the generation of digital test signals. A test program running in the test appliance controls the analog and digital modules. A synchronisation unit is provided to control the procedure of the test program.
It is sometimes necessary to connect several generated electrical signals to a device under test at the same time, wherein, in practice, only one function generator is to be used for this purpose, to deliver these signals. Measurement equipment for the investigation of devices under test is therefore embodied in a less complex manner and the signal paths from generation through to delivery are optionally shortened. In the case of a simultaneous connection of different measurement signals to a device under test, it should be noted that the time coherence, especially a relative phase angle between the measurement signals, is known. In particular, an occurrence of an error in which faulty conditions are generated in the device under test because of an unknown coherence or an incoherence between a first signal and a second signal of the function generator, which would not have occurred with the required coherence of these signals, must be precluded.
The object of the present invention is therefore to specify a function generator and a method for the delivery of electrical signals, in which the delivered signals comprise a known and rigidly defined phase angle, especially a known relative phase-angle value relative to one another. In particular, it should thus be possible to connect different electrical signals, for example, analog signals and/or digital signals with different modulations and different frequencies, to a device under test at the same time.